Thread-cutting device for sewing-machines



(No Model.) 2 Sheets-Sheet 1.

G. H. & -T. E. COLBY. THREAD CUTTING DEVICE FOR SEWING MACHINES.

No. 561,766. PatentedJune 9, 1896.

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(No M6661.) 2 Sheets-Sheet 2 C. H. 8B T. E. .GOLBY. THREAD CUTTING DEVICE FOR SEWING MACHINES.

1%. 561,766. P6666666 June 9, 1896.

WITNESSES" I INVENTORS M A MZQ UNITED STATES PATENT CHARLES H. COLBY AND THOMAS E. COLBY, OF BROOKLYN, NEW YORK.

THREAD-CUTTING DEVICE FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 561,766, dated June 9, 1896.

Application filed January 22, 1896. Serial No. 576,407. (No model) To aZZ whom it may concern:

Be it known that we, CHARLES H. COLBY and THOMAS E. COLBY, citizens of the United States, and residents of the city of Brooklyn, county of Kings, and State of New York, have invented a new and useful Improvement in Thread Cutting Devices for Sewing Machines; and we do hereby declare that the following is a full, clear, and exact description of the same.

This invention relates to thread-cutting devices for sewing-machines of the general class exemplified in an application for patent made by Herbert E. Hawes, and filed August 25, 1894, Serial No. 521,306, said application having been assigned to us as members of the firm of Colby da 60., of Brooklyn, New York. In the thread-cutting device described in said application Serial No. 521,806 athread cutting and clamping piece is swung across the needle-opening in the work-clamp on the completion of the stitching operation, so as to sever the thread from the work and at the same time clamp the free end of the thread until after the commencement of the next stitching operation, when the thread cutting and clamping piece is swung backward into position to sever the thread from the work on the completion of the stitching.

The general object of our invention is to provide an improved thread-cutting device which, after each cutting operation, is in position for the next cutting operation without the necessity of returning it, so that it is adaptable to all kinds of sewing-machines and particularly to buttonhole-sewing machines.

Another important object is to provide for clamping and holding the severed end of the thread in the needle until the completion of the next stitching operation, so that the ensuing operation of the cutting device will sever both the final thread of the buttonhole between. the needle and the work and the initial thread of the buttonhole between the thread-clamp and the work, and thus completely trim the work.

A further object is to conveniently provide for simultaneously cutting the threads of a plurality of buttonholes when stitched simultaneously by a multiple buttonhole-sewing machine of the kind exemplified in Letters Patent No. 44:1,058, granted to Thomas Colby, November 18, 1890.

We attain these and other important ends by the constructionhereinafter described, and illustrated in the accompanying drawings, in which like letters of reference designate the same parts in all the figures.

Figure l is a sectional side view representing the essential parts of a multiple buttonhole-sewing machine provided with a threadcutting device according to our invention. Fig. 2 is a plan view of the same. Figs. 3, l, 5, 6, 7, and 8 are detail views illustrating the successive steps in the operation of the said thread-cutting device.

A designates the work-table of a multiple buttonhole-sewing machine of the character described in Letters Patent No, 441,058 aforesaid; B, one of the work feeding clamps thereof; O, the prcsser-foot of the work-clamp B; D, the spring-depressed presserfoot arm; E, the carrier for the several work-clamps having the well-known vibratory and longitudinally-reciprocatory motion for making a buttonhole, and F the multiple presser-feetlifting device or lifter consisting of a rock shaft F, mounted on the carrier E beneath the arms of the presser-foot and having projections E to lift the arms D, and an operating-arm F which in practice is connected with a treadle, so that the several presserfeet may be elevated and lowered simultaneously by the foot of a single operator.

All the parts we have recited are substantially shown and described in said Letters Patent No. M1358, and therefore need no detailed description here.

In applying our improved thread-cutting device to this machine we mount a cuttingpiece G, having, by preference, a plurality of, in this instance, four equidistant radian ing bottom cutting edges G to revolve horizontally between the upper and lower plates H H, respectively, of each presser-foot G in such manner that when rotated the cutting edges G will successively swing from the side of the needle-opening I in the presser-foot to the end of said opening, where the needle rests before and after the stitching of the buttonhole, and thus between the uplifted needle and the work. We likewise form a cutting edge J on the lower plate H of the presser-foot at the end of the needle-opening I, so as to cooperate with the rotary cutting edges G and sever the thread between the needle and the work, as illustrated in Fig. 5.

On the top of the cutting-piece G, above each lower cutting edge G, we form a preferably beveled clampingjaw K to cooperate with a clamping-jaw K, formed on the upper plate H of the presser-t'oot at the end of the needle'opening I, as best shown in Figs. 5, 6,

and 7, so that when the thread is severed by the cutting-piece, as shown in Fig. 5, the upper severed end of the thread will at the same time be caught and clamped by the jaws K K, as shown in Figs. 6 and '7.

\Ve operate the thread cutting and clamping piece G so that in this application of'our invention on the completion of the stitching of a buttonhole a cuttiug'edge G will be rotated from the side to the end of the needleopening, so as to sever the thread and clamp the upper or free end thereof, and at the same time the suoceedingcutting edge G (if there are several cutting edges, as shown) will bebrought'into position for the next cutting operation. Then when the next buttonhole is stitched the thread end is held in the clamp until the completion of the stitching,

when there will be two adjoining threads to.

shaft L, which we mount in bearings on the presser-footand provide with a ratchet-wheel M, connected by a pawl N with an arm 0 on the rock-shaft F, the construction and arrangement-in this instance being such that when the rock-shaft is initially moved by the foot 01": the operator its projections F do not affect the 'presser-feet of the several workclamps, but through the ratchet connection described the rock-shaft "first operates the several thread cutting and clamping devices simultaneously, so as to sever and clamp the threads, and then raises the severalpresserfeet.

011 lowering the presser-feet for the succeeding buttonholes the cutting devices are of course not moved, the pawl N slipping over the teeth of the ratchet-wheel M.

It is evident that this rotary thread cutting and clamping device may be applied to any kind of sewing-machine, and it may be actuatedautomatically by a simple adaptation of the cam mechanism shown in the aforesaid application of Hawes, Serial No. 521,306.

The succeeding cutting ed ge We claim as our invention- 1. A sewing-machine provided with a threadcut-ting piece mounted to rotate between the needle and the work and with means for rotating the thread-cutting piece unidirectionally and intermittently so as to cut the thread at the end of each stitching operation.

2. A sewing-machine provided with a thread cutting piece mounted to rotate between the needle and the work, a thread-clamp, and means for rotating the thread-cutting piece unidirectionally and intermittently so as to out the thread at the end of a stitching operation, and for clamping the free end of the thread until the next operation of the cutting-- piece severs both the needle and clamp held ends from the work.

3. The'combination, with the worlefeeding clamp of a sewing-machine, of a thread-cutting piece mounted to revolve unidirectionally across the needle-opening in the clamp.

4. The combination, with the work-feeding clamp of a sewing-machine, of a thread-cutting piece mounted to revolve unidirectionally across the needle-opening in the work.- clamp'so as to out the thread, and a thread clamping device to hold the free end of the thread until the next operation of the rotary cutting -'piece severs both the needle and clamp held ends of the thread.

5. The combination, with the work-feeding clamp of a sewing-machine, said clamp having a cutting'edge and a clamping-jaw, of a thread cutting and clamping'piece and means for revolving said piece intermittently but unidirectionally across the needle-opening into engagement with the said cutting edge and clamping-jaw.

6. The com bination, with the work-feeding clamp of a sewing-machine, of a thread-cutting piece mounted to revolve unidirectionally,and having a plurality of radiating cutting edges, which edges are successively moved across the needle-opening in the workclamp. I

7. The combination, with the work-feedin g clamp of a sewing-machine, said clamp having a cutting edge and a clampiugjaw, of a thread cutting and clamping piece having a plurality of 'cuttin g edges and clampingjaws mounted to rotate successively into engagement with the cutting edge and clamping-jaw on the work-clamp.

in the clamp, of a resser-foot lifter, and operating connections, in eluding a ratchet-andpawl gear, between the thread-cutting piece and the resser-footliftenwhereby the threadcutting piece is rotated intermittently in one direction by the operation of the resser-foot lifter.

In testimony whereof we have hereunto set our hands this 46th day of June, 1895.

CHARLES H. COLBY. THOMAS E. COLBY.

In presence 0f- J ENNIE HOFFMANN, MINNIE SoHoLL. 

